The sixteenth-century Fountain of Neptune is one of Bologna’s most renowned landmarks. During the recent restoration activities of the monumental sculpture group, consisting in precious marbles and ...highly refined bronzes with water jets, a photographic campaign has been carried out exclusively for documentation purposes of the current state of preservation of the complex. Nevertheless, the highquality imagery was used for a different use, namely to create a 3D digital model accurate in shape and color by means of automated photogrammetric techniques and a robust customized pipeline. This 3D model was used as basic tool to support many and different activities of the restoration site. The paper describes the 3D model construction technique used and the most important applications in which it was used as support tool for restoration: (i) reliable documentation of the actual state; (ii) surface cleaning analysis; (iii) new water system and jets; (iv) new lighting design simulation; (v) support for preliminary analysis and projectual studies related to hardly accessible areas; (vi) structural analysis; (vii) base for filling gaps or missing elements through 3D printing; (viii) high-quality visualization and rendering and (ix) support for data modelling and semantic-based diagrams.
On the occasion of the recent restoration of the sixteenth century Neptune’s Fountain in Bologna, promoted by the municipality in 2015 to preserve one of the major town’s landmark, high-quality ...imagery has been acquired for documenting the current state of preservation of the marble and bronze surfaces before and during the restoration phases. Starting from this available detailed photographic campaign and using new tools developed to solve problems linked with some limitations of the captured imagery, authors produced a photogrammetry-based 3D model of the monumental sculpture group, reliable for both geometric features and colour reproduction consistency, in order to be used to support the supplementary activities not foreseen in the original project. The paper presents methods and techniques implemented to produce the 3D model of the fountain, besides its main actual applications as a basic tool to support different restoration activities: (i) reliable documentation of the actual state; (ii) high-quality visualization and rendering; (iii) technical outcomes and graphical representation extraction; (iv) study of original and current water supply system and simulation of the new project for the jets system and watergames; (v) new lighting design simulation; (vi) structural analysis; (vii) support to preliminary analysis and design studies related to hardly accessible areas; (viii) surface cleaning analysis; (ix) base for filling gaps or missing elements through 3D printing; (x) support for data modelling and semantic-based diagrams.
Efficient light transport simulation in participating media is challenging in general, but especially if the medium is heterogeneous and exhibits significant multiple anisotropic scattering. We ...present Principal-Ordinates Propagation, a novel finite-element method that achieves real-time rendering speeds on modern GPUs without imposing any significant restrictions on the rendered participated medium. We achieve this by dynamically decomposing all illumination into directional and point light sources, and propagating the light from these virtual sources in independent discrete propagation domains. These are individually aligned with approximate principal directions of light propagation from the respective light sources. Such decomposition allows us to use a very simple and computationally efficient unimodal basis for representing the propagated radiance, instead of using a general basis such as spherical harmonics. The resulting approach is biased but physically plausible, and largely reduces the rendering artifacts inherent to existing finite-element methods. At the same time it allows for virtually arbitrary scattering anisotropy, albedo, and other properties of the simulated medium, without requiring any precomputation.
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•We propose Principal-Ordinates Propagation (POP), a novel light transport scheme.•POP is a physically plausible method for rendering participating media in real-time.•A key insight is to use multiple, specifically aligned propagation domains.•Our solution can handle optically thin and thick media with anisotropic scattering.•Orthogonal to that, POP supports distant, local, and environment light sources.
Physically-based rendering systems use proprietary scene description formats. Thus, by selecting a given renderer for the development of a new technique, one is often constrained to test and ...demonstrate it on the limited set of test scenes available for that particular renderer. This makes it difficult to compare techniques implemented on different systems. We present a solution for automatic conversion among scene description formats used by physically-based rendering systems. It enables algorithms implemented on different renderers to be tested on the same scene, providing better means of assessing their strengths and limitations. Our system can be integrated with development and benchmarking APIs, lending to full orthogonality among algorithms, rendering systems, and scene files.
Neural volume rendering has gained significant popularity recently for its ability to synthesize novel scene views from a limited set of input images; one reason for this is the relatively ...rudimentary and experiential nature of the fundamental method used to obtain color output. However, the modeling and rendering results based on NeRF exhibit a relatively coarse level of detail. To overcome this challenge, we integrate the neural field's SDF (Signed Distance Function) representation with the PBR (Physically Based Rendering) material model for rendering to attain a more accurate scene representation by utilizing more interpretable parameters. In particular, the SDF is used to derive surface positions and normal for reflection modeling, while the PBR model is applied to regulate the reflection, diffuse, and potential transmission components. We evaluated our method in multiple scenes and found it achieved better reconstruction quality than the prior methods.
Depth reversal is the false perception whereby a receding or projecting spatial composition actually appears as the opposite of that composition. Such illusory effects are often forceful and have ...become a popular visual effect utilized in many site-specific installation artworks. However, the design approach most often employed is based on trial and error because the visual perception of depth-reversal illusion is often difficult to predict without actually seeing it in reality. Unfortunately, this approach demands extensive time and effort as well as increased material costs. Computer-aided design often provides a low-cost alternative for the design process; however, the feasibility of using a computer simulation in the design process depends upon the visual realism offered by the simulation. This study investigated the visual realism of a computer simulation with regard to envisioning the visual illusion of depth reversal. Perceptual studies were conducted to measure critical distances that occur when an observer experiences the visual perception of depth reversal in both physical and computer-simulated environments. The quantitative experimental results were used to establish the reliability of computer simulation for the design process of installation art that utilizes illusory visual effects of depth reversal from design ideation to exhibition planning.
Computer graphics is generally divided into two branches: real-time rendering and physically-based rendering. Conventional graphics processing units (GPUs) were designed to accelerate the former ...which is based on the standard Z-buffer algorithm. However, many applications in entertainment, science, and industry require high quality visual effects such as soft-shadows, reflections, and diffuse lighting interactions which are difficult to achieve with the Z-buffer algorithm, but are straightforward to implement using physically-based rendering methods. Physically-based rendering can already be implemented on present programmable GPUs. However, for physically-based rendering on GPUs, a large portion of the processing power is wasted due to low utilization of SIMD units. This is because the core algorithm of physically-based rendering, ray tracing, suffers from Single Instruction, Multiple Thread (SIMT) control flow divergences. In this paper, we propose the Dynamic Ray Shuffling (DRS) architecture for GPUs to address this problem. Our key insight is that the primary control flow divergences are caused by inconsistent ray traversal states of a warp, and can be eliminated by dynamically shuffling rays. Experimental results show that, for an estimated 0.11% area cost, DRS significantly improves the SIMD efficiency for the tested benchmarks from 41.06% to 81.04% on average. With this, the performance of a physically-based rendering method such as path tracing can be improved by 1.67X--1.92X, and 1.79X on average.
This work presents a novel interactive algorithm for simulation of light transport in clouds. Exploiting the high temporal coherence of the typical illumination and morphology of clouds we build on ...volumetric photon mapping, which we modify to allow for interactive rendering speeds—instead of building a fresh irregular photon map for every scene state change we accumulate photon contributions in a regular grid structure. This is then continuously being refreshed by re-shooting only a fraction of the total amount of photons in each frame. To maintain its temporal coherence and low variance, a low-resolution grid is initially used, and is then upsampled to the density field resolution on a physical basis in each frame. We also present a technique to store and reconstruct the angular illumination information by exploiting properties of the standard Henyey–Greenstein function, namely its ability to express anisotropic angular distributions with a single dominating direction. The presented method is physically plausible, conceptually simple and comparatively easy to implement. Moreover, it operates only above the cloud density field, thus not requiring any precomputation, and handles all light sources typical for the given environment, i.e., where one of the light sources dominates.
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► A real-time physically based light transport solution for clouds presented. ► An amortization scheme for photon beam mapping developed for this purpose. ► A new unimodal radiance representation based on Henyey–Greenstein function used. ► A novel physically based upsampling scheme employed to increase rendering quality.
Cultural Heritage Predictive Rendering Happa, Jassim; Bashford-Rogers, Tom; Wilkie, Alexander ...
Computer graphics forum,
September 2012, Letnik:
31, Številka:
6
Journal Article
Recenzirano
High‐fidelity rendering can be used to investigate Cultural Heritage (CH) sites in a scientifically rigorous manner. However, a high degree of realism in the reconstruction of a CH site can be ...misleading insofar as it can be seen to imply a high degree of certainty about the displayed scene—which is frequently not the case, especially when investigating the past. So far, little effort has gone into adapting and formulating a Predictive Rendering pipeline for CH research applications. In this paper, we first discuss the goals and the workflow of CH reconstructions in general, as well as those of traditional Predictive Rendering. Based on this, we then propose a research framework for CH research, which we refer to as ‘Cultural Heritage Predictive Rendering’ (CHPR). This is an extension to Predictive Rendering that introduces a temporal component and addresses uncertainty that is important for the scene’s historical interpretation. To demonstrate these concepts, two example case studies are detailed.
High‐fidelity rendering can be used to investigate Cultural Heritage (CH) sites in a scientifically rigorous manner. However, a high degree of realism in the reconstruction of a CH site can be misleading insofar as it can be seen to imply a high degree of certainty about the displayed scene‐which is frequently not the case, especially when investigating the past. So far, little effort has gone into adapting and formulating a Predictive Rendering pipeline for CH research applications. In this paper, we first discuss the goals and the workflow of CH reconstructions in general, as well as those of traditional Predictive Rendering. Based on this, we then propose a research framework for CH research, which we refer to as ‘Cultural Heritage Predictive Rendering’ (CHPR).
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